1. Field of the Invention
The present invention relates generally to container bases, and more particularly to stacking container bases that can withstand pasteurization.
2. Related Art
Stackable bases in large containers are desirable to improve ease of storing the container. However, some conventional stackable bases are not able to withstand the heat and pressures associated with pasteurization.
Plastic blow-molded containers, particularly those molded of PET, have been utilized in hot fill applications where the container is filled with a liquid product heated to a temperature in excess of 180° F. (82° C.), capped immediately after filling, and allowed to cool to ambient temperatures. Plastic blow-molded containers have also been utilized in pasteurization and retort processes, where a filled and sealed container is subjected to thermal processing and is then cooled to ambient temperatures. Pasteurization and retort methods are frequently used for sterilizing solid or semi-solid food products, e.g., pickles and sauerkraut, which may be packed into the container along with a liquid at a temperature less than 82° C. (180° F.) and then heated, or the product placed in the container that is then filled with liquid, which may have been previously heated, and the entire contents subsequently heated to a higher temperature.
Pasteurization and retort differ from hot-fill processing by including heating the contents of a filled container to a specified temperature, typically greater than 93° C. (200° F.), until the contents reach a specified temperature, for example 80° C. (175° F.), for a predetermined length of time. Retort processes also involve applying overpressure to the container.
Plastic containers have replaced or provided an alternative to glass containers for many applications. However, few food products that must be processed using pasteurization or retort are available in plastic containers. The rigors of such processing present significant challenges for the use of plastic containers, including containers designed for use in hot-fill processing. There remains a need to provide plastic containers that can withstand the rigors of pasteurization and retort processing in order to take advantage of the cost savings that can be realized through manufacture and recycling. The lighter weight of plastic containers as compared to glass can also advantageously reduce shipping costs.
What is needed then is an container base that overcomes shortcomings of conventional solutions.